//图片懒加载
function lazyload() {
    var temp1 = window.innerHeight || document.documentElement.clientHeight;
    var temp2 = document.documentElement.scrollTop || document.body.scrollTop;
    var showImgHeight = temp1 + temp2;
    var imgObjs = document.querySelectorAll("img");
    imgObjs.forEach(function (item) {
        if (item.offsetTop <= showImgHeight) {
            item.src = item.getAttribute("data");
        }
    }) 
        

}